Strawberry plant named `PS-1031`

ABSTRACT

This invention relates to a new and distinct winter planted short-day-type variety of strawberry known as `PS-1031`. This new variety is primarily adapted to the growing conditions of the central coast of California. It is particularly characterized by its strong vigorous plant with high yields, short petiolule length, large berry size and its ability to remain in fruit production from early April through November in Salinas, Calif. The fruit is particularly identifiable by its seedy tipped primaries and longitudinal creases occurring primarily during the spring months. The fruit is very attractive during the summer and fall months with acceptable flavor, firmness and holding quality.

SUMMARY OF THE INVENTION

The present invention relates to a new and distinct short-day-typestrawberry variety designated as `PS-1031`. This new variety is a resultof a cross of the variety claimed in U.S. Plant Pat. No. 8,205, and nowdesignated `PS-118`, and `Muir` (U.S. Plant Pat. No. 6,558). The varietyis botanically known as Fragaria×ananassa Duch.

This new variety of strawberry resulted from a breeding program jointlysponsored by Plant Sciences, Inc. and Berry R&D, Inc., both ofWatsonville, Calif., with the objective of developing new and distinctstrawberry varieties. The seedling resulting from the sforementionedcross was asexually propagated by stolons in a nursery located in LassenCounty, Calif., and was subsequently selected from a controlled breedingplot in Watsonville, Calif. in 1991. After its selection, the newvariety was further asexually propagated in Lassen County, Calif., bystolons and extensively tested over the next several years in fruitingfields near Watsonville, Calif. This propagation and reproduction hasdemonstrated that the combination of traits disclosed herein ascharacterizing the new variety are fixed and remain true to type throughsuccessive generations of asexual reproduction.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying color photographs show typical specimens of the newvariety at various stages of development as nearly true as it ispossible to make in color reproductions:

FIG. 1 shows typical plant parts of the new variety including leaves(both the lower surface of a mature terminal leaflet, and the uppersurface of a mature trifoliate leaf). Cross-sectional and longitudinalviews of mature fruit illustrate typical light flesh, and, conspicuouscore and core cavity. Also shown is an inflorescence with the primaryberry being mature and harvestable demonstrating typical fruitdistribution, shape and size;

FIG. 2 shows typical plant growth, flowering and fruitingcharacteristics in late July 1995. The photograph illustrates the plantvigor, inflorescences, and upright growth habit;

FIG. 3 shows a close-up of typical plant growth, flowering and fruitingcharacteristics in late July 1995;

FIG. 4 shows a close-up view of fruit harvested in mid July 1995 andpacked in a standard twelve-dry-pint-crate;

FIG. 5 disclosed the isozyme banding patterns for `PS-1031` comparedwith those of `PS-118` and `Selva`.

DESCRIPTION OF THE NEW VARIETY

`PS-1031` is primarily adapted to the climate and growing conditions ofthe central coast of California. This region provides the necessarywinter temperatures required for it to produce a strong vigorous plantthat remains in fruit production from April through November. The nearbyPacific ocean provides the needed humidity and cool temperatures tomaintain fruit quality during the summer production months.

`PS-1031` is a large vigorous plant. When provided with optimum chillingin the nursery propagation fields prior to being dug, and artificialcold storage prior to being planted, the plant of the new variety islarger and more vigorous than the varieties `PS-118` or `Selva` (U.S.Plant Pat. No. 5,266). `PS-1031` generally produces more runners perplant in the fruiting fields than either `PS-118` or `Selva`. Thefoliage of the new variety is noticeably lighter in color than `PS-118`but is similar in color to `Selva`. `PS-1031` leaves are larger and lessrounded than `PS-118`, but are similar in size and shape to `Selva`.`PS-1031` has more serrations per leaf than `PS-118` and fewerserrations than `Selva`. These serrations are also deeper than both.Petioles are longer in length than either `PS-118` or `Selva` and largerin diameter than `PS-118`. Petiolule length of `PS-1031` is considerablyshorter than both `PS-118` and `Selva`. Table 5 provides foliagecharacteristics of `PS-1031`, `PS-118` and `Selva`.

`PS-1031` is capable of long season fruit production with fruit ofexcellent size and good quality during teh entire season when providedwith optimum chilling in the nursery propagation fields and artificialcold storage prior to being planted. Initial studies indicate that`PS-1031` has a lower vernalization (chilling) requirement than `Selva`in order to optimize fruit production and plant vigor. Fruit productionbegins as early as the beginning of April in Salinas, Calif., and maycontinue into November if rains and cold temperatures do not prevent theharvest. April production is earlier and heavier than `PS-118` andsimilar to `Selva`. `PS-1031` season average fruit size is larger thaneither `PS-118` or `Selva`, with total yields greater than both (Table1).

The fruit of `PS-1031` is smoother with fewer longitudinal creases andbetter overall appearance and gloss than `Selva`. Table 3 provides asummary of fruit quality performance ratings. The primary berries of`PS-1031` tend to produce seedy tips at the apex of the fruit primarilyduring the early spring and under adverse weather conditions. Incomparison, `PS-118` tends to produce seedy tipped fruit during much ofthe season. The seeds of `PS-1031` are typically held even with thesurface of the fruit. In contrast, the seeds of `PS-118` tend toprotrude from the surface of the fruit. The fruit color of `PS-1031` isnoticeably lighter than `PS-118` but similar in color to `Selva`.`PS-1031` has a lighter internal flesh color than either `PS-118` dor`Selva`. The early spring fruit of `PS-1031` is less uniformly shapedthan `PS-118` with more longitudinal creases and wedge-shaped berries.By mid-summer the fruit of `PS-1031` becomes more uniformly conic inshape than either `PS-118` and `Selva`.

Flavor panels have rated `PS-1031` as having nearly comparable flavor to`Selva` (Table 4). The fruit of `PS-1031` is more susceptible to skincracking from rain than either `PS-118` or `Selva`. The totalinflorescence length of `PS-1031` is longer than `PS-118` and shorterthan `Selva`, especially during the summer months. The average primarypeduncle length of `PS-1031` is similar in length but thinner than`PS-118` or `Selva`. The primary pedicel of `PS-1031` is shorter than`Selva` and generally thinner than `Selva` or `PS-118`. Flowers andripening fruit are less visible above the canopy of the plant than`PS-118`. A summary of inflorescence characteristics for `PS-1031`,`PS-118` and `Selva` is contained in Table 6.

SPECIFIC DESCRIPTION OF THE NEW VARIETY

The following is a detailed description of `PS-1031`, including thevariety's morphological, electrophoretic, pest and disease reactioncharacteristics. This detailed description is based on observationstaken during May through July of 1995 in Salinas, Calif. Inthoseinstances in which characteristics were rated at different times, thedate of evaluation is listed. These measurements and ratings were madefrom plants dug from a high-elevation nursery located in Lassen County,Calif. in October 1994 and planted in Salinas, Calif. in November 1995.The phenotypic characteristics of the new variety may vary slightly,depending upon variations in environmental factors, including weather(temperature, humidity and light intensity), day length, soil type,location, and time of year, without any change in the genotype of theplant. `PS-1031` has not been observed under all possible environmentalconditions. Color terminology follows the Munsell Book of Colors,Munsell Color, Baltimore, Md. (1976).

FRUIT CHARACTERISTICS

`PS-1031` fruit, fruit production and runner production (fruiting field)characteristics are compared to those of `PS-118` and `Selva` in Table1.

                  TABLE 1                                                         ______________________________________                                        1994 market fruit yield, fruit size and runner production                     characteristics from plants harvested from April through                      November 1994 of `PS-1031` from a high elevation nursery                      (McArthur, California) compared with standard cultivars dug                   October 20, 1993 and planted November 9, 1993 in Salinas,                     California.                                                                                              AVERAGE                                                     APRIL    TOTAL    FRUIT    AVERAGE                                            YIELD    YIELD    SIZE     RUNNERS/                                  CULTIVAR GM/PL    GM/PL    G/FR     PL                                        ______________________________________                                        `PS-1031`                                                                              81       1625     24.8     0.50                                      `PS-118` 43       1351     21.7     0.12                                      `SELVA`  90       1414     22.8     0.20                                      ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Comparison of primary fruit characteristics of `PS-1031`,                     `PS-118` and `Selva` from Salinas, California, July 27, 1995*.                CHARACTER `PS-1031`   `PS-118`    `SELVA`                                     ______________________________________                                        Munsell Color                                                                           7.5R 3/10 to                                                                              7.5R 3/10 to                                                                              7R 4/11**                                             7.5R 4/10   7.5R 2/8**                                              Fruit Length                                                                            3.7         3.8         4.4                                         mean (cm)                                                                     Fruit Width                                                                             4.1         4.0         4.2                                         mean (cm)***                                                                  Calyx Diameter                                                                          4.3         5.4         4.1                                         mean (cm)                                                                     Sepals/Berry                                                                            14.8        15.0        15.8                                        mean                                                                          ______________________________________                                         *`PS118` and `Selva` evaluated July 17, 1995.                                 **`PS118` and `Selva` fruit color according to Nelson et al. U.S. Plant       Pat. No. 8,205.                                                               ***Width is measured across the widest part of the berry, typically the       shoulders.                                                               

                  TABLE 3                                                         ______________________________________                                        Comparison of 1994 fruit quality characteristics of                           `PS-1031`, `PS-118` and `Selva` from Salinas, California.*                    CHARACTER    `PS-1031`  `PS-118` `SELVA`                                      ______________________________________                                        Skin Firmness                                                                              7.3        8.3      7.6                                          Fruit Appearance                                                                           7.0        7.7      6.8                                          Fruit Gloss  7.5        8.2      6.6                                          ______________________________________                                         *Results are from replicated holding tests performed from April through       October 1994. Ratings are based on a scale from 1-10; the higher the          rating, the stronger the skin and the more attractive and glossy the          berry.                                                                   

                  TABLE 4                                                         ______________________________________                                        Comparison of 1995 flavor test summary of                                     `PS-1031`, `PS-118` and `Selva`.*                                             CHARACTER   `PS-1031`   `PS-118` `SELVA`                                      ______________________________________                                        Rating      2.0         3.5      2.4                                          ______________________________________                                         *Results are an average of 3-4 flavor tests from fruit harvested from         Salinas, California after being held for 2-3 days in cold storage. Rating     are based on scores of 1-5, 5 being the best.                            

The fruit of `PS-1031` is large in size and characteristicallysymmetrically conic in shape from about mid-June through November.Primary berries are typically wider to equal across the shoulders thanlong with longitudinal creases and irregular shapes commonly occurring.The secondary and tertiary berries are typically longer than wide andmostly symmetrically conic in shape. The fruit surface is medium red incolor with a very light colored flesh to white at the core. See Table 2for fruit comparison characteristics.

The fruit surface is typically smooth with the seeds generally heldflush to the surface with some seeds slightly protruding from thesurface of the fruit. The seeds are yellow and only darken slightly withprolonged exposure to direct sunlight. The seeds are generally spacedevenly over the surface of the berry with seedy tipped fruit commonlyoccurring during the early spring. These berries may develop severecreases radiating longitudinally from the seedy tips to the shoulders ofthe fruit. The fruit becomes more uniformly shaped with fewer seedy tipsand longitudinal creases during the summer and fall months. The skin ofthe fruit is considered moderately firm with acceptable gloss. Tables 3and 4 summarize fruit quality and flavor characteristics, respectively.

The calyx of the primary berry is medium in diameter with someoverlapping sepals. The calyx attaches slightly below the base of thefruit with necked fruit very uncommon. The sepals are elliptical toovate in shape with acute apexes and only occasionally serrated. Fruitskin is considered very susceptible to cracking due to rain. Pollinationmay be affected by rain resulting in seedy tipped fruit and smallmalformed berries.

PLANT CHARACTERISTICS

The plant of `PS-1031` is large in size with multiple crowns producingfew runners if given the proper chilling levels prior to being dug, andartifically, prior to being planted. Excessive chilling will result inan over-vigorous plant with a reduction in total fruit yield andincreased runner production. The foliage grows upright on relativelylong thick petioles. The plant canopy remains relatively open if exposedto the proper chilling and cold storage levels, but may become dense ifover-chiled and/or over-stored. The plant canopy has a relativelymedium-light colored appearance.

FOLIAGE CHARACTERISTICS

`PS-1031` foliage characteristics are compared to those of `PS-118` and`Selva` in Table 5.

                  TABLE 5                                                         ______________________________________                                        Comparison of leaf characteristics of `PS-1031`, `PS-118` and                 `Selva` from Salinas, California, May 19, 1995.                               CHARACTER   `PS-1031`   `PS-181`  `SELVA`                                     ______________________________________                                        Munsell Leaf Color                                                                        7.5GY 3/4   7.5GY 3/4*                                                                              7.5GY 4/4*                                  (upper Surface)                                                                           to 7.5GY 2/4                                                      Terminal Leaflet                                                                          9.9         8.4       9.8                                         Length                                                                        mean (cm)                                                                     Terminal Leaflet                                                                          8.2         7.7       8.3                                         Width                                                                         mean (cm)                                                                     Terminal Leaflet                                                                          1.21        1.09      1.19                                        ratio (L/W)                                                                   Petiole Length                                                                            22.9        20.1      19.8                                        mean (cm)                                                                     Petiole Width                                                                             5.3         4.7       5.2                                         mean (mm)                                                                     Petiolule Length                                                                          5.9         10.0      10.8                                        mean (mm)                                                                     Serrations/leaf                                                                           22.1        20.7      24.9                                        Serration depth                                                                           6.4         5.8       5.2                                         mean (mm)                                                                     ______________________________________                                         *`PS118` and `Selva` leaf color according to Nelson et al., U.S. Plant        Pat. No. 8,205.                                                          

The foliage of `PS-1031` is relatively large in size, moderately glossy,medium-light in color and moderately rugose. The terminal leaflet ismuch longer than wide as described by the length/width ratio. Table 5summarizes foliage comparison characteristics. Leaflets have manyrelatively large and deep serrations at the margins, with moderatelyacute apexes. These serrations typically occur singly, very seldom indoubles. Petioles are considered long and thick in diameter with bractleaflets commonly occurring singly or in pairs. Petiolules areconsidered short in length. Pubescence on the petioles grow irregularlyperpendicular to the petiole and irregularly parallel to the upper andlower leaf surface.

FLOWERS AND INFLORESCENCES

`PS-1031` inflorescence characteristics are compared to those of`PS-118` and `Selva` in Table 6.

                  TABLE 6                                                         ______________________________________                                        Comparison of inflorescence charateristics of `PS-1031`,                      `PS-118` and `Selva` from Salinas California, July 27, 1995*.                 CHARACTER    `PS-1031`  `PS-118` `SELVA`                                      ______________________________________                                        Inflorescence                                                                              32.9       30.8     36.0                                         Length                                                                        mean (cm)                                                                     Primary Peduncle                                                                           19.2       19.0     20.0                                         Length                                                                        mean (cm)                                                                     Primary Peduncle                                                                           3.6        4.2      4.2                                          Width                                                                         mean (mm)                                                                     Primary Pedicel                                                                            6.8        6.3      9.0                                          Length                                                                        mean (cm)                                                                     Primary Pedicel                                                                            2.2        2.3      2.5                                          Width                                                                         mean (mm)                                                                     ______________________________________                                         *`PS118` and `Selva` evaluated July 17, 1995.                            

The inflorescences of `PS-1031` are medium in length, extending theflowers and fruit beyond the foliage during the spring months. As theplant grows and becomes more vigorous during the summer and fall, thefruit may remain slightly concealed within the canopy of the plant. Theprimary peduncle is considered medium in length and thickness,especially at the time of the evaluation. The pedicel holding theprimary berry is considered medium-short in length and thin and mayoriginate singly from the apex of the primary peduncle or from one ofthe secondary peduncles. Secondary and tertiary berries are borne onpedicels arising from secondary peduncle apexes. Table 6 summarizesinflorescence comparison characteristics.

Flowers are large in size and seldom visible above the canopy of theplant. Anthers produce ample pollen for good pollination except duringthe early season and rainy periods when seedy tips and creased fruit mayoccur. Flowers produce an average of 5 to 8 obovate shaped petals perflower. Typically a single bract leaf is borne on a short petiole whichoriginates at the primary peduncle apex alongside the base of one of thesecondary peduncles. Occasionally a trifoliate will develop instead ofthe single bract leaf. Bract leaves may also occur singly at the apex ofsecondary peduncles. Pubescence occurs on all peduncles and pedicels,growing irregularly perpendicular to both these surfaces.

ISOZYMES IN LEAF EXTRACT

`PS-1031` isozyme banding characteristics are compared to those of`PS-118` and `Selva` in Table 7.

                  TABLE 7                                                         ______________________________________                                        `PS-1031` Isozyme banding patterns                                            compared to `PS-118` and `Selva`.                                             CULTIVAR          PGI    PGM                                                  ______________________________________                                        `PS-1031`         A4     C2                                                   `PS-118`          A7     C4                                                   `Selva`           A2     C2                                                   ______________________________________                                    

Studies of protein polymorphism in strawberry by the starch gelelectrophoresis method were conducted at Plant Sciences, Inc. tocharacterize this newly developed variety and distinguish it fromsimilar appearing varieties.

Isozymes were extracted from young leaves and characterized, usingstarch gel electrophoresis techniques. The following isozymes werecharacterized: phosphoglucoisomerase (PGI: EC 5.3.1.9) andphosphoglucomutase (PGM: EC 2.7.5.1).

The testing used both field and greenhouse grown plant material, allgrown in Watsonville, Calif. Newly mature leaves (0.5 g fresh weight)from the growing crowns were used. Samples were collected in themorning, held at 4° and analyzed within six hours.

The tissue preparation, extraction and staining methods utilized are asreported in S. Arulsekar and D. E. Parfitt, "Isozyme Analysis Proceduresfor Stone Fruits, Almong, Grape, Walnut, Pistachio, and Fig",HortScience 21(4): 928-933.

Following electrophoresis, the gel was sliced and stained for eachenzyme system. Banding patterns were interpreted as they developed, andgel slices were fixed in 50% glycerol.

The isozyme banding patterns of `PS-1031`, compared to `Selva` and`PS-118`, are given in FIG. 5. The pattern and band densities for PGMare distinctly different between `PS-1031` (C2) and `PS-118` (C4). Thepattern and band densities for PGI are distinctly different between`PS-1031` (A4) and both `PS-118` (A7) and `Selva` (A2). The combinationof isozyme patterns shown, derived from specific techniques described,and the other characteristics of `PS-1031` identify it with certainty asa unique strawberry variety.

A series of molecular markers have been assigned to this new variety forunique identification.

PEST REACTIONS

The new variety may not be resistant to any of the known insects,diseases or viruses common in California. It is known to be susceptibleto the two-spotted spider mite, aphid and flower thrip. It is also knownto be susceptible to grey fruit mold, angular leafspot and powderymildew. The susceptibility of the new variety to any of the viruscomplexes of California has not been determined.

We claim:
 1. A new and distinct variety of strawberry plant designated`PS-1031`, as herein described and illustrated.